Cooling apparatus

ABSTRACT

Disclosed herein is a cooling apparatus including a body on or below which a power module is mounted; a first cooling unit formed in the body in a longitudinal direction of the body to have first fluid passing therethrough and including an inlet to which the first fluid is introduced at one side of the longitudinal direction of the body and an outlet from which the first fluid is discharged at the other side thereof and a second cooling unit formed in the first cooling unit in a shape intersecting with first cooling unit to have second fluid passing therethrough.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2012-0070785, filed on Jun. 29, 2012, entitled “Cooling Apparatus”, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a cooling apparatus.

2. Description of the Related Art

As energy consumption has increased around the world, effective maximizing the use of limited energy has attracted great attention.

As a power module has been widely used, consumers' need for multi-functional and small-sized products has increased. However, a heating problem that arises due to this need can decrease the performance of an entire module.

Thus, in order to increase the efficiency of a power module and to ensure high reliability, there is a need for a structure for overcoming the heating problem. In order to resolve the heating problem, a cooler for cooling a power module may be formed on a surface of a power module (U.S. Pat. No. 6,344,686).

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a cooling apparatus for increasing a cooling effect of a power module.

Further, the present invention has been made in an effort to provide a cooling apparatus for overcoming a warpage phenomenon due to a temperature difference.

According to a first preferred embodiment of the present invention, there is provided a cooling apparatus including: a body on or below which a power module is mounted; a first cooling unit formed in the body in a longitudinal direction of the body to have first fluid passing therethrough and including an inlet to which the first fluid is introduced at one side of the longitudinal direction of the body and an outlet from which the first fluid is discharged at the other side thereof and a second cooling unit formed in the first cooling unit in a shape intersecting with first cooling unit to have second fluid passing therethrough.

The second cooling unit may have a cylindrical shape.

The second cooling unit may have an oval cylindrical shape in such a way that a diameter measured in the longitudinal direction of the body is greater than a diameter measured in a height direction of the body.

The second cooling unit may have a polygonal shape.

The second cooling unit may be formed in such a way that a height thereof is reduced in the longitudinal direction of the body.

The second cooling unit may have a streamlined shape.

The cooling apparatus may further include a third cooling unit that is formed in the first cooling unit and is formed on at least one of an upper portion and a lower portion of the second cooling unit.

The third cooling unit may include a plurality of columns that protrude from the second cooling unit.

The second cooling units may be in plural.

The plurality of second cooling units may be spaced apart from each other in the longitudinal direction of the body.

The plurality of second cooling units may be spaced apart from each other at equidistant intervals.

An interval at which the plurality of second cooling units are spaced apart from each other may be gradually reduced toward the other side of the longitudinal direction of the body from one side thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a cooling apparatus according to an embodiment of the present invention;

FIG. 2 is a perspective view of a cooling apparatus according to another embodiment of the present invention;

FIG. 3 is a perspective view of a cooling apparatus according to another embodiment of the present invention;

FIG. 4 is a perspective view of a cooling apparatus according to another embodiment of the present invention; and

FIG. 5 is a cross-sectional view of a cooling apparatus according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The objects, features, and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side”, and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the related art would obscure the gist of the present invention, the description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

FIG. 1 is a perspective view of a cooling apparatus 100 according to an embodiment of the present invention.

Referring to FIG. 1, the cooling apparatus 100 may include a body 110, a first cooling unit 120, and a second cooling unit 130.

The cooling apparatus 100 may be formed on or below a power module (not shown). The cooling apparatus 100 dissipates outwards heat generated from the power module.

According to the present embodiment, the cooling apparatus 100 may have a structure in which a single second cooling unit 130 having a cylindrical shape is formed in the first cooling unit 120.

The power module may be mounted on or below the body 110. In addition, the first cooling unit 120 and the second cooling unit 130, through which fluids pass, may be formed in the body 110. The body 110 may transfer heat generated from the power module to the fluids. The body 110 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include aluminum (Al), iron (Fe), copper (Cu), nickel (Ni), a stainless alloy, or the like.

The first cooling unit 120 may be formed in the body 110. In addition, the first cooling unit 120 may be formed through the body 110 in a longitudinal direction of the body 110. According to the present embodiment, the first cooling unit 120 may have a cylindrical shape. However, the shape of the first cooling unit 120 is not limited thereto. That is, the first cooling unit 120 may be easily modified by one of ordinary skill in the art as long as the first cooling unit 120 may be formed through the body 110. First fluid may pass through the first cooling unit 120. One side of the first cooling unit 120 may be an inlet 121 to which the first fluid is introduced. In addition, the other side of the second cooling unit 130 may be an outlet 122 from which second fluid is discharged. The first fluid may cool the power module formed on the body 110 while passing from the inlet 121 of the first cooling unit 120 to the outlet 122. That is, the first fluid may absorb heat generated from the power module while passing through the first cooling unit 120. The first fluid may be gas such as air passing through the first cooling unit 120. Alternatively, the first fluid may be liquid such as cooling water passing through the first cooling unit 120. Alternatively, the first fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The second cooling unit 130 may be formed in the first cooling unit 120. The second cooling unit 130 may be formed through the first cooling unit 120. In this case, the second cooling unit 130 may be formed to intersect with the first cooling unit 120. The second cooling unit 130 may have a cylindrical shape. As shown in FIG. 1, the second cooling unit 130 may have a cylindrical shape in such a way that a diameter measured in a longitudinal direction of the body 110 may be greater than a diameter measured in a height direction of the body 110. However, the shape of the second cooling unit 130 is not limited to the cylindrical shape shown in FIG. 1 and is easily changed by one of ordinary skill in the art. The second fluid may pass through the second cooling unit 130. The second fluid may cool the first fluid that passes through the first cooling unit 120 while passing through the second cooling unit 130. The second fluid may be gas such as air passing through the second cooling unit 130. Alternatively, the second fluid may be liquid such as cooling water passing through the second cooling unit 130. Alternatively, the second fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

FIG. 2 is a perspective view of a cooling apparatus 200 according to another embodiment of the present invention.

Referring to FIG. 2, the cooling apparatus 200 may include a body 210, a first cooling unit 220, and a second cooling unit 230.

According to the present embodiment, the cooling apparatus 200 may have a structure in which a single second cooling unit 230 having a polygonal shape is formed in the first cooling unit 220.

A power module may be mounted on or below the body 210. In addition, the first cooling unit 220 and the second cooling unit 230, through which fluids pass, may be formed in the body 210. The body 210 may transfer heat generated from the power module to the fluids. The body 210 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include Al, Fe, Cu, Ni, a stainless alloy, or the like.

The first cooling unit 220 may be formed in the body 210. In addition, the first cooling unit 220 may be formed through the body 210 in a longitudinal direction of the body 210. According to the present embodiment, the first cooling unit 220 may have a cylindrical shape. However, the shape of the first cooling unit 220 is not limited thereto. That is, the first cooling unit 220 may be easily modified by one of ordinary skill in the art as long as the first cooling unit 220 may be formed through the body 210. The first fluid may pass through the first cooling unit 220. One side of the first cooling unit 220 may be an inlet 221 to which the first fluid is introduced. In addition, the other side of the second cooling unit 230 may be an outlet 222 from which the second fluid is discharged. The first fluid may cool the power module formed on the body 210 while passing from the inlet 221 of the first cooling unit 220 to the outlet 222. That is, the first fluid may absorb heat generated from the power module while passing through the first cooling unit 220. The first fluid may be gas such as air passing through the first cooling unit 220. Alternatively, the first fluid may be liquid such as cooling water passing through the first cooling unit 220. Alternatively, the first fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The second cooling unit 230 may be formed in the first cooling unit 220. The second cooling unit 230 may be formed through the first cooling unit 220. In this case, the second cooling unit 230 may be formed to intersect with the first cooling unit 220. According to the present embodiment, the second cooling unit 230 may have a polygonal shape such as a pentagonal shape. As shown in FIG. 2, the second cooling unit 230 may have a left portion having a rectangular cross section, which is relatively close to the inlet 221 of the first cooling unit 220. In addition, the second cooling unit 230 may have a right portion having a triangular cross section, which is relatively close to the outlet 222 of the first cooling unit 220. Since the right portion of the second cooling unit 230 may taper gradually, when the first fluid flows along an external surface of the second cooling unit 230, vortex of the first fluid may be prevented from being generated. The second fluid may pass through the second cooling unit 230. The second fluid may cool the first fluid that passes through the first cooling unit 220 while passing through the second cooling unit 230. The second fluid may be gas such as air passing through the second cooling unit 230. Alternatively, the second fluid may be liquid such as cooling water passing through the second cooling unit 230. Alternatively, the second fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

FIG. 3 is a perspective view of a cooling apparatus 300 according to another embodiment of the present invention.

Referring to FIG. 3, the cooling apparatus 300 may include a body 310, a first cooling unit 320, and a second cooling unit 330.

According to the present embodiment, the cooling apparatus 300 may have a structure in which a single second cooling unit 330 having a streamlined shape is formed in the first cooling unit 320.

A power module may be mounted on or below the body 310. In addition, the first cooling unit 320 and the second cooling unit 330, through which fluids pass, may be formed, the body 310. The body 310 may transfer heat generated from the power module to the fluids. The body 310 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include Al, Fe, Cu, Ni, a stainless alloy, or the like.

The first cooling unit 320 may be formed in the body 310. In addition, the first cooling unit 320 may be formed through the body 310 in a longitudinal direction of the body 310. According to the present embodiment, the first cooling unit 320 may have a cylindrical shape. However, the shape of the first cooling unit 320 is not limited thereto. That is, the first cooling unit 320 may be easily modified by one of ordinary skill in the art as long as the first cooling unit 320 may be formed through the body 310. The first fluid may pass through the first cooling unit 320. One side of the first cooling unit 320 may be an inlet 321 to which the first fluid is introduced. In addition, the other side of the second cooling unit 330 may be an outlet 322 from which the second fluid is discharged. The first fluid may cool the power module formed on the body 310 while passing from the inlet 321 of the first cooling unit 320 to the outlet 322. That is, the first fluid may absorb heat generated from the power module while passing through the first cooling unit 320. The first fluid may be gas such as air passing through the first cooling unit 320. Alternatively, the first fluid may be liquid such as cooling water passing through the first cooling unit 320. Alternatively, the first fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The second cooling unit 330 may be formed in the first cooling unit 320. The second cooling unit 330 may be formed through the first cooling unit 320. In this case, the second cooling unit 330 may be formed to intersect with the first cooling unit 320. According to the present embodiment, the second cooling unit 330 may have a streamlined shape. That is, the second cooling unit 330 may have a left portion of which an external surface has a curved shape, which is relatively close to the inlet 321 of the first cooling unit 320. In addition, a right portion of the second cooling unit 330, which is relatively close to the outlet 322 of the first cooling unit 320, may taper gradually and has a sharp end. Since the second cooling unit 330 has a streamlined shape, resistance against the first fluid may be minimized. In addition, since the second cooling unit 330 has a streamlined shape, when the first fluid flows along an external surface of the second cooling unit 330, vortex of the first fluid may be prevented from being generated. The second fluid may pass through the second cooling unit 330. The second fluid may cool the first fluid that passes through the first cooling unit 320 while passing through the second cooling unit 330. The second fluid may be gas such as air passing through the second cooling unit 330. Alternatively, the second fluid may be liquid such as cooling water passing through the second cooling unit 330. Alternatively, the second fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

FIG. 4 is a perspective view of a cooling apparatus 400 according to another embodiment of the present invention.

Referring to FIG. 4, the cooling apparatus 400 may include a body 410, a first cooling unit 420, a second cooling unit 430, and a third cooling unit 440.

The cooling apparatus 400 may be formed on or below a power module. The cooling apparatus 400 dissipates outward heat generated from the power module.

The power module may be mounted on or below the body 410. In addition, the first cooling unit 420 and the second cooling unit 430, through which fluids pass, may be formed in the body 410. The body 410 may transfer heat generated from the power module to the fluids. The body 410 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include Al, Fe, Cu, Ni, a stainless alloy, or the like.

The first cooling unit 420 may be formed in the body 410. In addition, the first cooling unit 420 may be formed through the body 410 in a longitudinal direction of the body 410. According to the present embodiment, the first cooling unit 420 may have a cylindrical shape. However, the shape of the first cooling unit 420 is not limited thereto. That is, the first cooling unit 420 may be easily modified by one of ordinary skill in the art as long as the first cooling unit 420 may be formed through the body 410. The first fluid may pass through the first cooling unit 420. One side of the first cooling unit 420 may be an inlet 421 to which the first fluid is introduced. In addition, the other side of the second cooling unit 430 may be an outlet 422 from which the second fluid is discharged. The first fluid may cool the power module formed on the body 410 while passing from the inlet 421 of the first cooling unit 420 to the outlet 422. That is, the first fluid may absorb heat generated from the power module while passing through the first cooling unit 420. The first fluid may be gas such as air passing through the first cooling unit 420. Alternatively, the first fluid may be liquid such as cooling water passing through the first cooling unit 420. Alternatively, the first fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The second cooling unit 430 may be formed in the first cooling unit 420. The second cooling unit 430 may be formed through the first cooling unit 420. In this case, the second cooling unit 430 may be formed to intersect with the first cooling unit 420. The second cooling unit 430 may have a cylindrical shape. As shown in FIG. 4, the second cooling unit 430 may have an oval cylindrical shape in such a way that a diameter measured in a longitudinal direction of the body 410 may be greater than a diameter measured in a height direction of the body 410. However, the shape of the second cooling unit 430 is not limited to the oval cylindrical shape shown in FIG. 4 and is easily changed by one of ordinary skill in the art. The second fluid may pass through the second cooling unit 430. The second fluid may cool the first fluid that pass through the first cooling unit 420 while passing through the second cooling unit 430. The second fluid may be gas such as air passing through the second cooling unit 430. Alternatively, the second fluid may be liquid such as cooling water passing through the second cooling unit 430. Alternatively, the second fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The third cooling unit 440 may be formed in the first cooling unit 420. In addition, the third cooling unit 440 may be formed on an upper surface of the second cooling unit 430. As shown in FIG. 4, the third cooling unit 440 may include a plurality of columns that protrude from the upper surface of the second cooling unit 430. In FIG. 4, the third cooling unit 440 includes a plurality of rectangular columns. However, the shape of the third cooling unit 440 is not limited thereto and is easily changed by one of ordinary skill in the art. The third cooling unit 440 may transfer heat of the first fluid that passes therethrough to the second cooling unit 430. The first fluid may be effectively cooled by the third cooling unit 440. In FIG. 4, the third cooling unit 440 is formed on the upper surface of the second cooling unit 430. However, alternatively, the third cooling unit 440 may be formed on a lower surface of the second cooling unit 430, or may be simultaneously formed on upper and lower surfaces of the second cooling unit 430. The third cooling unit 440 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include Al, Fe, Cu, Ni, a stainless alloy, or the like.

FIG. 5 is a cross-sectional view of a cooling apparatus 500 according to another embodiment of the present invention.

Referring to FIG. 5, the cooling apparatus 500 may include a body 510, a first cooling unit 520, and a plurality of second cooling units 530.

According to the present embodiment, the cooling apparatus 500 may have a structure in which a plurality of second cooling units 530 are formed in the first cooling unit 520.

A power module 600 may be mounted on or below the body 510. In addition, the first cooling unit 520 and the second cooling units 530, through which fluids pass, may be formed in the body 510. The body 510 may transfer heat generated from the power module 600 to fluids. The body 510 may be formed of a plastic material or a metal material in order to effectively transfer heat. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polystyrene resin, an acrylonitrile/styrene/butadiene terpolymer resin (ABS resin), a polycarbonate resin, a polyethylene terephthalate resin, or the like. Examples of the metal material include Al, Fe, Cu, Ni, a stainless alloy, or the like.

The first cooling unit 520 may be formed in the body 510. In addition, the first cooling unit 520 may be formed through the body 510 in a longitudinal direction of the body 510. According to the present embodiment, the first cooling unit 520 may have a cylindrical shape. However, the shape of the first cooling unit 520 is not limited thereto. That is, the first cooling unit 520 may be easily modified by one of ordinary skill in the art as long as the first cooling unit 520 may be formed through the body 510. The first fluid may pass through the first cooling unit 520. One side of the first cooling unit 520 may be an inlet 521 to which the first fluid is introduced. In addition, the other side of the second cooling units 530 may be an outlet 522 from which the second fluid is discharged. The first fluid may cool the power module 600 formed on the body 510 while passing from the inlet 521 of the first cooling unit 520 to the outlet 522. That is, the first fluid may absorb heat generated from the power module 600 while passing through the first cooling unit 520. The first fluid may be gas such as air passing through the first cooling unit 520. Alternatively, the first fluid may be liquid such as cooling water passing through the first cooling unit 520. Alternatively, the first fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

The second cooling units 530 may be formed in the first cooling unit 520. The second cooling units 530 may be formed through the first cooling unit 520. In this case, the second cooling units 530 may be formed to intersect with the first cooling unit 520. According to the present embodiment, the second cooling units 530 may be formed to be plural. The plurality of second cooling units 530 may be arranged in a longitudinal direction of the body 510. In FIG. 5, the second cooling units 530 each have a streamlined shape, but are not limited thereto. That is, each of the second cooling units 530 may have various shapes such as an oval shape or a polygonal shape. In addition, the third cooling unit 440 shown in FIG. 4 may be formed on at least one of an upper surface and a lower surface of each of the second cooling units 530. An interval at which the second cooling units 530 are spaced apart from each other may be reduced toward the outlet 522 of the first cooling unit 520 from the inlet 521 of the first cooling unit 520. A temperature of the first fluid may increase towards the outlet 522 of the first cooling unit 520 from the inlet 521 of the first cooling unit 520. Thus, in order to increase cooling efficiency of the first fluid, an interval between the second cooling units 530 may be gradually reduced toward the outlet 522 of the first cooling unit 520 from the inlet 521 of the first cooling unit 520. An interval between the second cooling units 530 may be easily changed by one of ordinary skill in the art. That is, an interval at which the second cooling units 530 are spaced apart from each other may be gradually reduced, or alternatively, may be gradually increased. Alternatively, the second cooling units 530 may be spaced apart from each other at equidistant intervals. The second fluid may pass through the second cooling units 530. The second fluid may cool the first fluid that passes through the first cooling unit 520 while passing through the second cooling units 530. The second fluid may be gas such as air passing through the second cooling units 530. Alternatively, the second fluid may be liquid such as cooling water passing through the second cooling units 530. Alternatively, the second fluid may be gas-liquid mixing fluid, supercritical fluid, or the like.

According to the above-described embodiments of the present invention, a cooling apparatus may be configured in such a way that first fluid may cool a power device and second fluid may cool the first fluid, thereby increasing a cooling effect. As the first fluid absorbs heat generated from a power module, a temperature of the first fluid may increase toward an outlet of a first cooling unit from an inlet of the first cooling unit. Thus, the first fluid may have different temperatures at the inlet and the outlet of the first cooling unit. The second fluid may cool the first fluid between the inlet and the outlet of the first cooling unit. That is, a temperature difference of the first fluid between the inlet and outlet may be reduced by the second fluid. By reducing the temperature difference of the first fluid between the inlet and outlet, a warpage phenomenon of the cooling apparatus due to the temperature difference may be overcome.

In addition, since a second cooling unit may be formed in a portion of the first cooling unit through which the first fluid pass, an area through which the first fluid passes may be reduced at the portion of the first cooling unit. As the area through which the first fluid passes is reduced, a velocity of the first fluid is increased, and thus, cooling performance may be regionally improved.

According to the above-described embodiments of the present invention, a cooling apparatus may be configured in such a way that first fluid may cool a power device and second fluid may cool the first fluid, thereby increasing a cooling effect.

In the cooling apparatus, by reducing a temperature difference of the first fluid between an inlet and an outlet of the first fluid, a warpage phenomenon of the cooling apparatus due to the temperature difference may be overcome.

In addition, in the cooling apparatus, since a second cooling unit may be formed in a portion of the first cooling unit through which the first fluid pass, an area through which the first fluid passes may be reduced at the portion of the first cooling unit. Thus, a velocity of the first fluid is increased, and thus, cooling performance may be regionally improved.

Although the embodiments of the present invention have been disclosed for illustrative purposes, it will be appreciated that the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention.

Accordingly, any and all modifications, variations, or equivalent arrangements should be considered to be within the scope of the invention, and the detailed scope of the invention will be disclosed by the accompanying claims. 

What is claimed is:
 1. A cooling apparatus, comprising: a body on or below which a power module is mounted; a first cooling unit formed in the body in a longitudinal direction of the body to have first fluid passing therethrough and including an inlet to which the first fluid is introduced at one side of the longitudinal direction of the body and an outlet from which the first fluid is discharged at the other side thereof; and a second cooling unit formed in the first cooling unit in a shape intersecting with first cooling unit to have second fluid passing therethrough.
 2. The cooling apparatus as set forth in claim 1, wherein the second cooling unit has a cylindrical shape.
 3. The cooling apparatus as set forth in claim 2, wherein the second cooling unit has an oval cylindrical shape in such a way that a diameter measured in the longitudinal direction of the body is greater than a diameter measured in a height direction of the body.
 4. The cooling apparatus as set forth in claim 1, wherein the second cooling unit has a polygonal shape.
 5. The cooling apparatus as set forth in claim 4, wherein the second cooling unit is formed in such a way that a height thereof is reduced in the longitudinal direction of the body.
 6. The cooling apparatus as set forth in claim 1, wherein the second cooling unit has a streamlined shape.
 7. The cooling apparatus as set forth in claim 1, further comprising a third cooling unit formed in the first cooling unit and formed on at least one of an upper portion and a lower portion of the second cooling unit.
 8. The cooling apparatus as set forth in claim 7, wherein the third cooling unit includes a plurality of columns that protrude from the second cooling unit.
 9. The cooling apparatus as set forth in claim 1, wherein the second cooling units are in plural.
 10. The cooling apparatus as set forth in claim 9, wherein the plurality of second cooling units are spaced apart from each other in the longitudinal direction of the body.
 11. The cooling apparatus as set forth in claim 10, wherein the plurality of second cooling units are spaced apart from each other at equidistant intervals.
 12. The cooling apparatus as set forth in claim 10, wherein an interval at which the plurality of second cooling units are spaced apart from each other is gradually reduced toward the other side of the longitudinal direction of the body from one side thereof. 